Sputter coating apparatus with end feed

ABSTRACT

A sputter-coating apparatus comprises an elongated chamber provided at one end with a loading door and having internally a plurality of pairs of guide rails between which vertical platelike workpieces are stood. A carriage is horizontally displaceable above the workpieces and is provided with a plurality of suspended sputter-coating cathodes connected together as a rack whose lower end is guided between the lower rails. All of the rails are formed as U-section channels to receive the workpieces between their flanks, which are provided with adjustable spacers in order to maintain an exact positioning of the workpieces.

States Patent Glaser et al.

[ June 12, 1973 sPUTTER-CoATING APPARATUS WITH 3,616,451 10/1971 Gallez204/298 END FEED [75] Inventors: Hans Joachim Gliiser, PrimaryExaminer-John H. Mack Gelsenkirchen; Horst Beckmann, AssistantExaminerSidney S. Kanter Bochum, both of Germany Att0rneyl(arl F. Ross[73] Assignee: Flachglas AG Delong-Detag,

v Gelsenklrchen, Germany [57] ABSTRACT [22] Filed: .Mar. 31, 1972 r Asputter-coatmg apparatus compnses an elongated PP Nov: 240,002 chamberprovided at one end with a loading door and having internally aplurality of pairs of guide rails be- [30] Foreign Application PriorityDat tween which vertical platelike workpieces are stood. A

A r 2 1971 Germ n P 21 l 6 190 O carriage is horizontally displaceableabove the workp a y pieces and is provided with a plurality of suspendedsputter-coating cathodes connected together as a rack gill. whose lowerend is guided between the lower rails. A [58] Fie'ld 4/192 298 of therails are formed as U-section channels to receive the workpieces betweentheir flanks, which are pro- [56] References Cited vided with adjustablespacers in order to maintain an 1 UNITED STATES PATENTS exactpositioning of the workpieces.

3,414,503 12/1968 Brichard 204/298 9 Claims, 3 Drawing Figures l 1 i '1'1 V1 :70 \n a? Ida I 8 .79 pi i /9 Fl Fl Fl I! II 56 W/A a 'Y A VPAIENTED Y 2 I975 SHEET 1 BF 2 SPUTTER-COATING APPARATUS WITH END FEEDFIELD OF THE INVENTION The present invention relates to an apparatus forthe sputter-coating of a sheet-like workpiece and, more particularly toan apparatus for use in the sputtercoating of a glass, ceramic, orsynthetic-resin plate.

BACKGROUND OF THE INVENTION workpiece) are lifted by a crane and thenpainstakingly fitted, usually with the help of a worker or two standingon top of the treatment chamber, down into the apparatus. Care must beexercised to prevent breaking of the workpieces, which often are aslarge as square meters. In order to increase efficiency by loading andunloading the treatment apparatus as quickly as possible all of thesheets are fitted into a large frame which is dropped by automatic meansinto the top of the treatment chamber. Such equipment is extremelycostly and, when a workpiece of different thickness is used, it is oftennecessary to allow several days of downtime for readjustment of thespacing between parallel racks.

Furthermore the electrodes are usually arranged horizontally in verticalplanar arrays which are displaced vertically up and down next to thestationary workpiece, or more often between two workpieces. To this endthe rack of electrodes (sputtering cathodes) is mounted as a carriage onfour vertical threaded spindles which are driven to raise and lowerthese electrodes. Once again this complicated arrangement is difficultto adjust and at best rarely gives perfectly uniform coatings to theworkpieces since the complexity of the drive, inter alia, makes itimpossible to maintain a uniform electrode-workpiece gap.

OBJECTS OF THE INVENTION SUMMARY OF THE INVENTION The above objects areattained according to the present invention in an apparatus wherein'theworkpieces are held in place by upper and lower guides. The electrodeshang vertically from a carriage which is horizontally reciprocal in theupper region of the treatment chamber, and the lower end of theelectrode rack is received between adjacent lower guides which form anupwardly open guide slot.

According to another feature of the present invention the carriage forthe electrodes rides on a pair of rails in the upper region of thetreatment chamber. These rails are independent of the upper guides sothat the carriage will have no effect on these guides as it isreciprocated back and forth during the sputtering operations. Preferablythe rails are located on opposite sides and outwardly of the array ofguides.

Each lower guide is preferably a straight upwardly open channel providedwith a plurality of spaced-apart anti-friction rollers. The upper guideis a downwardly open channel without rollers so that the workpiece (thebody to be coated clipped to a rigid support plate or frame) can heslipped in the end of the apparatus, horizontally. These various guidechannels can be shifted transversely for any desired spacing of theworkpieces from the electrodes.

According to a further feature of this invention the electrodes arearrayed in a plurality of racks which are straight for planar workpiecesor curved for warped or intentionally profiled workpieces. Each rackhangs through a respective slot formed in the carriage, and is blockedinto an exact position in the slot. Similarly the lower end of each rackis provided with rollers rotatable about vertical axis and rising on theouter edges of the lower guide channels.

DESCRIPTION OF THE DRAWING The above and other objects, features, andadvantages of the invention will become more readily apparent from thefollowing description, reference being made to the accompanying drawingin which:

FIG. 1 is a longitudinal section through the apparatus according to thepresent invention;

FIG. 2 is a transverse section taken along line ll II of FIG. 1, theelectrode racks being removed for simplification of the view; and

FIG. 3 is a side elevational view of a rack of electrodes according tothe present invention.

SPECIFIC DESCRIPTION The sputter-coating apparatus according to thepresent invention has a housing I with a removable end wall 6 that isheld in place by means of wing nuts 39 to form an elongated gastightchamber in this housing. Plates 3 to be coated are held by adjustableclips 56 on rigid supports 2 in a vertical position, and the chamber isevacuated by a pump 40 connected at its rear end by means of a conduit7.

More specifically each support plate 2 rides on rollers 17 journaledbetween the flanks 10 of an upwardly open U-section lower guide channel9. The flanks 10 of each channel 9 are provided with inwardly projectingalignment or spacer screws 11 which can be screwed in and out so thatthe plate 2 is snugly received in the channels 9, no rollers 17 beingnecessary. Adjustment screws 11 are also provided here to preventlateral movement of a support plate 2. The upper guide channels aresecured at their ends by means of support blocks 12 to the roof or topof the housing 1 and to the lower guide channels 9 by means ofrespective uprights 14. The channels 8 and 9 are parallel to each other.The upright 14 defines, as seen in FIG. 1, the maximum left-hand travelof a plate between the guides 8 and 9. A carriage 4 rides by means of acylindrical wheel 41 allowing expansion of the carriage under heatingand a circumferentially grooved wheel 42 on a round rail 18a supportedon one side wall 43 of the housing and on a sharp-edged rail 18b securedto and defining the position of the other side wall 44 of the housing 1.This carriage comprises a plurality of heavy steel plates 20 suspendedby stout support beams 22 from a grid 45. This grid has a length Isubstantially one-fifth of the length L of the housing 1, and is able tofit between the uprights 14 and the end wall having the conduit 7. Sincethe workpieces are sheets pushed in against the uprights 14 and have alength equal to L which is equal to substantially three-fifths L theentire carriage 4 will be able to move past the entire workpiece 3. Areversible motor 46 carries a cable drum 19 on which is wound a cable 47that is spanned over pulleys 48 and connected to one of the plates 20 ofthe carriage 4. As the motor rotates in one direction the carriage 4travels in one longitudinal direction and when the motor is reversed, bymeans of simple limit switches, the carriage returns.

Each pair of plates 20 defines a slot 49 in which hangs a planarelectrode rack 21 comprising three live cathodes connected by means ofend contacts 25 and cables 30 to a three-phase alternating-currentsource 50 and hanging vertically between planes defined by flankingguides 8 and 9. Four grounded electrodes 26 are interleaved with theelectrodes to form a comb and all of the electrodes 5 and 26 arecylindrical sleeves through which water is circulated from a cooler 51by a pump 52 through flexible conduits 31. These elec trodes are arrayedparallel to each other in an upright position in a rectangular frameformed by horizontal cross pieces 24a and 24b interconnected by sidemembers 23. The lower crosspiece 24b is provided with four smallhorizontal rollers 36 which engage the flanks of the channels 9 so thatthe electrode assembly 21 does not wobble from side to side as it isdisplaced by the carraige 4 through the chamber 1. The upper crosspiece24 is provided with two outwardly projecting flanges 27 which lie on topof the confronting edgesof the plates 20. Spacer blocks 28 are employedto insure an exact positioning of the upper portion of each rack 21relative to the respective slot 49. Screws 29 may be used to secure theflanges 27 to the plates 20. The clips 56 ensure an exact positioning ofeach plate 3 on its frame 2.

In order to prevent the conduits 31 and cable 30 from kinking andinterfering with operation of the device a counterweight 35 suspended ona cable 34 from a pulley 53 is provided, with the cable 34 attached bymeans of a bracket 54 to the center of the respective conduit or cable.In addition depending side members 32 are provided on the carriage 4with guide shields 33 which will prevent such kinking or interference.

It should also be noted that, shown in FIG. 2, when an undulating orotherwise nonplanar workpiece 3' is to be coated, similarly curvedelectrodes 5' may be employed, but these particular sheets 3 beingreceived directly between the guides 8 and 9, without a support frame 2.

A process gas such as argon is fed from a source 55 through conduits 37into distributing pipes 38 which extend across the full width of thechamber 1 at its top and bottom adjacent the door 6.

The apparatus is operated as follows:

Twelve workpieces 3 carried on support frames 2 are slid into theapparatus between respective channels 8 and 9 and up against theuprights 14. Then the door 6 is closed and secured by means of thewingnut dogs 39.

The suction pump 40 is actuated and once pressure in the chamber 1 hasdropped below a predetermined level argon is admitted from theperforated pipes 38 to thoroughly sparge the chamber. The power source50 is now hooked up and the pump 52 is started in order to circulatecooling water through the cathodes 5. With the carriage 4 in theantechamber behind upright 14, the gas discharge between the electrodesis ignited. Then the motor 46 is started to draw the carriage along theworkpieces and thereby to sputter coat that face of each workpieceturned toward the cathodes 5. Cathodes of different metals are used toobtain multilayer coating.

Since the electrode racks 21 are snugly guided both at their tops and attheir bottoms the spacing between each electrode 5 and the workpieces 3remains almost perfectly uniform as these racks are displaced throughthe chamber. Proper adjustment by use of the blocks 27 and the seatingof the supports 15 allows any irregularity to be canceled out withlittle difficulty.

The door 6 permits the workpieces to be loaded horizontally into theapparatus so that complicated equipment for lifting and guiding theseworkpieces 3 is not required.

We claim:

1. A sputter-coating apparatus comprising:

a gastight chamber;

suction means connected to said chamber for at least partiallyevacuating same;

at least one upper horizontal rail in said chamber;

at least one lower horizontal rail in said chamber below and parallel tosaid upper rail, a sheetlike workpiecebeing retainable in an uprightposition between said upper rail and said lower rail;

means forming with said lower rail a lower guide;

a horizontally displaceable carriage in said chamber above said upperrail;

a rack of sputter-coating electrodes having an upper end attached tosaid carriage and a lower end engaged with said guide; and

means for displacing said carriage horizontally in said chamber withsaid lower end riding along said guide and thereby moving saidelectrodes past said sheetlike workpiece while sputtering a coatingthereon.

2. The apparatus defined in claim 1 wherein said means forming saidguide is another such lower rail parallel to the first-mentioned lowerrail, said apparatus including another such upper rail parallel to thefirstmentioned upper rail, another such sheetlike workpiece beingretained between the second-mentioned upper and lower rails.

3'. The apparatus defined in claim 2, wherein said rails are formed aschannels having flanks, each workpiece being received between the flanksof one of the upper rails and between the flanks of the correspondinglower rail.

4. The apparatus defined in claim 3 wherein said chamber has a top,bottom, side, and end walls, one of said end walls being provided with adoor, said upper rails being suspended from said top wall, and saidlower rails being supported on said bottom wall.

5. The apparatus defined in claim 3 wherein said rails are provided withspacing means on their flanks for snugly engaging the faces of aworkpiece received therebetween.

6. The apparatus defined in claim 5 wherein said spacing means aredisplaceable transverse to the longitudinal axis of said rails.

7. The apparatus defined in claim 3 wherein each electrode rack includesa plurality of elongated vertical electrodes and upper and lower crossmembers interconnecting said electrodes at said upper and lower ends ofsaid rack, said lower cross member being provided with'a plurality ofrollers engaging the flanks of said workpieces resting on said rollers.

1. A sputter-coating apparatus comprising: a gastight chamber; suctionmeans connected to said chamber for at least partially evacuating same;at least one upper horizontal rail in said chamber; at least one lowerhorizontal rail in said chamber below and parallel to said upper rail, asheetlike workpiece being retainable in an upright position between saidupper rail and said lower rail; means forming with said lower rail alower guide; a horizontally displaceable carriage in said chamber abovesaid upper rail; a rack of sputter-coating electrodes having an upperend attached to said carriage and a lower end engaged with said guide;and means for displacing said carriage horizontally in said chamber withsaid lower end riding along said guide and thereby moving saidelectrodes past said sheetlike workpiece while sputtering a coatingthereon.
 2. The apparatus defined in claim 1 wherein said means formingsaid guide is another such lower rail parallel to the first-mentionedlower rail, said apparatus including another such upper rail parallel tothe first-mentioned upper rail, another such sheetlike workpiece beingretained between the second-mentioned upper and lower rails.
 3. Theapparatus defined in claim 2, wherein said rails are formed as channelshaving flanks, each workpiece being received between the flanks of oneof the upper rails and between the flanks of the corresponding lowerrail.
 4. The apparatus defined in claim 3 wherein said chamber has atop, bottom, side, and end walls, one of said end walls being providedwith a door, said upper rails being suspended from said top wall, andsaid lower rails being supported on said bottom wall.
 5. The apparatusdefined in claim 3 wherein said rails are provided with spacing means ontheir flanks for snugly engaging the faces of a workpiece receivedtherebetween.
 6. The apparatus defined in claim 5 wherein said spacingmeans are displaceable transverse to the longitudinal axis of saidrails.
 7. The apparatus defined in claim 3 wherein each electrode rackincludes a plurality of elongated vertical electrodes and upper andlower cross members interconnecting said electrodes at said upper andlower ends of said rack, said lower cross member being provided with aplurality of rollers engaging the flanks of said lower rails.
 8. Theapparatus defined in claim 7 wherein said rollers are rotatable aboutvertical axes.
 9. The apparatus defined in claim 3 wherein each saidlower rail is provided with a plurality of rollers rotatable aboutrespective parallel horizontal axes, said workpieces resting on saidrollers.